Yet again, Jews in Europe are grieving. Saturday's brutal shooting at the Jewish Museum in Brussels was a stark reminder that, for its Jewish communities, Europe is rapidly becoming a dark continent, one where extreme violence lurks behind the constant stream of anti-Zionist and anti-Semitic invective found on extremist websites and mainstream media outlets alike.

Four people were murdered in the museum shooting. Two of them were a couple from Tel Aviv, vacationing in the Belgian capital. The third was a female volunteer at the museum, while the fourth was a 23 year-old museum employee who was hospitalized in critical condition and who died shortly afterwards from his injuries. The assault was eerily reminiscent of the Islamist terror attack in 2012 at a Jewish school in the French city of Toulouse, in which three young children and a rabbi were similarly shot at close range by Mohammed Merah, an individual with dual French and Algerian citizenship who entered the global Islamist terror network following visits to Afghanistan and Pakistan.

It just so happens that I am writing these lines from Jerusalem, where I am one of several speakers at a major conference on anti-Semitism organized by the Vidal Sassoon International Center for the Study of Anti-Semitism at the Hebrew University. As the news from Brussels broke on Saturday night, hundreds of Israelis were gathering in cafes and bars to watch the final of the European Cup soccer tournament. In the informal conversations I had with fellow spectators, I encountered anger and disgust, but little surprise–this is Europe we're talking about, after all. And to its immense credit, the Israeli government's official response to the attack reflected these public sentiments. "This act of murder is the result of constant incitement against Jews and their state," declared Prime Minister Benjamin Netanyahu. "Slander and lies against the State of Israel continue to be heard on European soil even as the crimes against humanity and acts of murder being perpetrated in our region are systematically ignored."

When it comes to spreading fear among Jews, Belgium is, in fact, one of the worst offenders. The the latest annual survey of global anti-Semitic incidents and expressions from Tel Aviv University's Stephen Roth Institute noted that "the countries in which the situation and sense of vulnerability seem to be the worst were Hungary, France, and Belgium." Indeed, anyone tempted to think that the Brussels attack was an isolated aberration would do well to consider the depressingly long list of anti-Semitic incidents in Belgium that presaged it.

Last year, an anti-Semitism watchdog group reported a 23 percent increase in antisemitic attacks in 2012 from the previous year (when you remember that many such incidents go unreported, the number is likely to be higher.) As Netanyahu asserted in his response to the museum attack, these physical manifestations of anti-Semitism are enabled by the incitement which underpins them. There was, for example, the Brussels concert of the former Pink Floyd vocalist, and professional Israel-hater, Roger Waters, which featured a pig-shaped balloon emblazoned with a Star of David. A website for the teaching of history run by the Belgian Education Ministry featured a cartoon by the anti-Semitic Brazilian artist, Carlos Latuff, which compared Israel with Nazi Germany through a representation of a dead concentration camp victim alongside a dead Palestinian, their limbs arranged in the shape of a swastika. In February this year, passengers on a Belgian train were informed over the speaker system, "Ladies and gentlemen, we are approaching Auschwitz. All Jews are requested to disembark and take a short shower." Earlier this month, police in Brussels used water cannon to disperse a mob of anti-Semites who had gathered for an event featuring the anti-Semitic French provocateur, Dieudonné M'bala M'bala, and Laurent Louis, a Belgian parliamentarian who has regularly issued anti-Zionist and anti-Semitic statements.

It's often quipped that European governments have a decent record of commemorating dead Jews, as evidenced by the numerous Holocaust memorials across the continent, and a pretty awful record when it comes to protecting live ones. The imperative of guaranteeing freedom of speech necessarily limits any actions that governments can take against anti-Semitic incitement, but that should not prevent European leaders from explicitly recognizing where this poison springs from. It is not enough to say, as did the president of the European Commission, Jose Manuel Barroso, that the Brussels atrocity "was an attack on European values which we cannot tolerate." Only when Europe's politicians finally acknowledge that the continent's culture of Israel-hatred–expressed through boycott campaigns, degrading films and cartoons, frequent analogies between Israel and Nazi Germany or apartheid-era South Africa, and much else besides–is what lies behind this deadly violence, will we finally be able to say that some progress in confronting this social disease has been made.